The present invention relates to a compiler vectorizing system for generating a vectorized object program from a source program described in a high level language in a computer system which allows the vectoring operation to be achieved (hereinafter referred to as a vector computer).
In a vector computer, vectoring operation allows an extremely high speed execution as compared with the scalar operation. In order to fully utilize the capability of the vector computer as much as possible, in a compiler for the vector computer, it is important to increase the ratio (vectoring factor) of a portion of the object program which is executed by the vector operation. To this end, there exists a compiler vectorizing system.
Conventionally, in this type of the compiler vectoring system, if a variable defined or referenced within a loop is positively defined within a single iterative process, it can be arrayed for vectorization while if there exists a conditional branch within the loop and whether the variable is defined or not depends on whether the condition for each iterative process is met or not, then the loop cannot be vectorized. As a result, the vectorizing factor of the object program for the vector computer is lowered.